Multi-pulley and force problem

  • Thread starter narfarnst
  • Start date
  • #1
14
0

Homework Statement


http://i829.photobucket.com/albums/zz220/narfarnst/problem.jpg

Find T1 through T5 and the force on the right side of the diagram above.
(The force balances the weight, so the system is stationary).
EDIT: Oh, and the pulleys and ropes are massless and there is no friction.

Homework Equations


F=ma, various rearrangements of T=m(g+/-a)


The Attempt at a Solution


Based on mostly intuition I've concluded that T1=mg (very sure about that one).
I also think that T2 and T3 equally share the weight, so T2=T3=1/2mg.
T4 has to equal mg+F for it to keep the system up
And I'm not sure about T5 but I'm thinking that it equals mg because the system isn't accelerating.
But I'm not at all 100% sure an these.

Thanks!
 

Answers and Replies

  • #2
rl.bhat
Homework Helper
4,433
8
The single rope has three segments. Each segments must have the same tension. That is the basic constrain in the pulleys.
 
  • #3
2,034
305
Based on mostly intuition I've concluded that T1=mg (very sure about that one).
Intuition is fine, if you can then find a reason why it is so. Gravity and
the tension of the rope are the only forces on the block, so they
must be equal and opposite.

I also think that T2 and T3 equally share the weight, so T2=T3=1/2mg.
Because the pulleys have no friction and no mass, there must be the
same tension in the ropes on both sides. (if there were not they would
start to accelerate infinitely fast)
T4 has to equal mg+F for it to keep the system up
Ok
And I'm not sure about T5 but I'm thinking that it equals mg because the system isn't accelerating.
but then the forces on the top pulley would be unbalanced
 

Related Threads on Multi-pulley and force problem

  • Last Post
Replies
2
Views
3K
Replies
2
Views
4K
  • Last Post
Replies
1
Views
18K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
12
Views
2K
  • Last Post
Replies
5
Views
2K
  • Last Post
Replies
10
Views
878
  • Last Post
Replies
8
Views
808
L
  • Last Post
Replies
12
Views
3K
  • Last Post
Replies
15
Views
1K
Top